Air Emissions in My Community web tool: Frequently asked questions

How do I operate the web tool?

The web tool is designed to be simple to use, so only a few key pointers are provided in this FAQ for you to enjoy full functionality of the web tool.

Four interactive chart views are provided that are listed across the top of the dashboard. Left mouse click on these to view.

Whenever the mouse pointer changes to a hand icon, a function or action is available by left mouse clicking that item.

In most views, additional information is available when the mouse pointer is positioned over chart items, for instance the individual bars in a bar chart, or slices in a pie chart.

Selection of substances, locations, sectors or units is provided by clicking the Menu icon. The data and charts may be exported to either Excel or a graphics file by clicking on the Export button.

How should the emissions information in the web tool be used?

The web tool has been developed to provide public information about the sources of common air pollutants and their relative contributions to emissions in local areas. It can be used to identify the largest contributors to emissions in local areas and to compare total emissions and their sources in two or more areas. Since the relationship between local emissions and air quality is quite complex, caution should be used in inferring air quality in any particular area (see the following question).

While the web tool provides information on the key emission sources in a geographical area, it cannot be directly used to estimate local air quality.

How do the emissions relate to air quality?

Air quality is defined by the concentration of a substance emitted into ambient air, while air emissions are defined as the mass of a substance emitted within a specified area. The relationship between emissions in an area and local air quality is quite complex. Meteorology (wind speed and direction, temperature and rain) and topography determine how emissions are dispersed from their sources in ambient air. In general, the influence of an emission source on ambient concentrations decreases rapidly with distance from the source. In addition to primary emissions, photochemical formation of secondary pollutants, termed photochemical smog, also contributes to air pollution. Medium and longer range transport of emissions in ambient air may also impact on local air quality, when emissions from a large distant source are transported by wind to that location. In general, areas with higher emissions per unit area (tonnes per square kilometre) are likely to experience poorer air quality when compared to areas with lower emissions per unit area.

Where does the emissions data in the web tool come from?

The web tool data is a sub-set of the NSW Air Emissions Inventory data developed by the NSW Environment Protection Authority (EPA). The inventory provides emission estimates for over a thousand different substances from natural and human-made sources across the NSW greater metropolitan region (PDF 210KB) (GMR). Emissions are estimated using international best practice techniques. More information on the inventory and how emissions are estimated can be found in:

Why is the emissions data in the web tool for the 2008 calendar year?

The NSW air emissions inventory is compiled every five years. It is a major undertaking that takes three highly skilled people over three years to plan, compile and document. The inventory is used by the EPA to:

identify key emission sources

develop cost effective programs for improving air quality

track changes in emissions over time to evaluate the effectiveness of pollution reduction programs.

Since emissions and contributions of key sources tend to change quite modestly over time, 5-yearly inventory updates provide a reasonable timeframe for evaluating any changes in emissions due to growth in activity and/or effectiveness of emission reduction measures.

The EPA is currently updating the inventory for the 2013 calendar year.

How does the NSW Air Emissions Inventory differ from the National Pollutant Inventory (NPI)?

The National Pollutant Inventory (NPI) is a Commonwealth program that is implemented in partnership with States and Territories, including NSW. The NPI provides yearly updates for emissions from commercial and industrial facilities. The NSW Air Emissions Inventory is a NSW program that is updated every 5 years and plays a key role in managing air pollution from all key sources in NSW. The key differences between the two inventories are:

The NPI presents annually updated information on emissions of 93 substances to air, water and land as well as information on waste transfers from industrial and commercial facilities in NSW. The NSW Air Emissions Inventory reports emissions to air for over 1000 substances from all natural and human-based emission sources in the NSW greater metropolitan region (GMR), where over 75 per cent the NSW population resides

The NPI includes reporting thresholds to determine whether a facility is required to report their emissions. In 2011-2012, about 900 facilities in NSW reported to the NPI. Of these, around two-thirds were scheduled premises under the POEO Act, which are required to hold an environment protection licence and are listed on the POEO Public Register

The NSW Air Emissions Inventory includes about 1100 scheduled premises and 5000 non-scheduled premises within the NSW GMR, regardless of their size. A wide range of non-premises based human and natural diffuse emission sources (aggregated emissions data - AED) are also estimated and reported, including: motor vehicles; domestic wood heating; aerosol and solvent use; and lawn mowing. The NPI AED for NSW is sourced from the NSW Air Emissions Inventory, so these data are equivalent

The NSW Air Emissions Inventory estimates and reports premises and diffuse emission source data in greater detail than the NPI to support regulatory analysis. For example, power station emissions are separately reported for boilers, coal handling and stockpiles, while motor vehicle emissions are separately reported for five different vehicle types. All emissions are estimated and reported on a monthly, daily and hourly varying basis. In contrast, the NPI reports annual aggregated emissions by facility.

What are the health effects of the substances in the web tool?

Many of the substances included in the web tool have adverse health effects. Substance information (PDF 615KB) is available, which provides information on the health effects of substances included in the web tool.